With the progress of computer-related industries, the point of sales (POS) system is becoming more and more powerful and is widely used by the retail, financial, hospitality or other industries.
The early point of sales system has the integrated design, and therefore is not suitable for carrying due to the large size and heavy weight. In recent years, point of sales system with detachable host and expansion base has been gradually developed, so that the host can be easily detach from the expansion base and carried when necessary.
When the detachable host and the expansion base are engaged with each other, the electrical connection portion of the host and the electrical connection portion of the expansion base are connected to each other. However, since the user may perform a click operation on the host, the host and the expansion base may shake relative to each other during the operation if the engagement between the host and the expansion base is not stable. After a long period of time, a poor electrical connection between the host and the expansion base or even a malfunction may be resulted.